Current research leads us to believe that nerves may play a regulatory role in dentin deposition in teeth. Reparative or response dentin is known to form when dentin is stimulated by a cavity, by abrasion, heat, cold or dental caries. This response dentin forms in the pulp adjacent to the stimulated zone. Resection of nerves to the teeth results in an exaggerated dentinal response to stimulation. This dentin is not limited to the area of stimulation but forms throughout the pulp. Moreover, it is altered ranging in structure from osteoid to tubular dentin. It is the purpose of the proposed study to detemine if neurotrophism and/or neural conduction plays a role in dentinogensis. It is again the aim of these studies to determine what effect each component of the nervous system has on the activation of pulpal cells concerned with reparative processes as measured by the uptake of specific precursors to RNA, DNA and general protein synthesis. Finally it is our aim to visualize the specific receptors, using radioligands, responsible for initiation of pulpal responses to trauma.